Pneumatic timer system



Oct. 13, 1964 L. M. HUBBY PNEUMATIC TIMER SYSTEM Filed Aug. 14. 1962United States Patent Office 3,152,611 Patented Oct. 13, 1964 3,152,611PNEUMATIC TIMER SYSTEM Laurence M. Hubby, Bellaire, Tex., assignor toTexaco Inc., New York, N.Y., a corporation of Delaware Filed Aug. 14,1962, Ser. No. 216,836 7 (Ilaims. (Cl. 137-62414) This invention isconcerned with a pneumatic timer generally and more specificallyconcerns an improved pneumatic timer arrangement that is especiallyadapted for use with gas lift wells or the like.

Heretofore it has been generally the practice in connection with gaslift oil well pumping operations, to employ a timer for each well thatregulates the length of time during which gas under pressure is admittedto the annulus of the well that is being gas lifted. The gas liftoperation (which is well known) involves intermittent introduction ofgas under pressure to the annulus of the well which is closed at the topand bottom thereof. Such gas pressure, when it is introduced enters thetubing through gas lift valves and causes accumulated fluids, e.g. oil,to be driven up out of the well through the tubing. Each lifting cycleis arranged in its time duration to lift all of the accumulated liquideach time gas pressure is applied. Then the intervening time periodwhich fol lows each application of the pressurized gas, allows time forthe producing liquid to accumulate downhole in the tubing ready for thenext so-called gas lift cycle.

As indicated previously, the timing control for gas lift pumpingoperations has heretofore most frequently been one that is basicallyclock work control. This prior arrangement involved a pilot valve actionwhich in turn would control the application of pneumatic pressure to themain control valve for applying gas pressure to the well. Such priorarrangement had various drawbacks including the fact that the clock workcontrol was relatively delicate in nature, so that rough handling wouldoften necessitate repairs. Furthermore, since such operations are mostoften in isolated areas, the clock work must of necessity have been aspring wound type. Consequently there was a periodic requirement forwinding the clock work, to maintain the gas lift operation. In additionsuch clock work controls were relatively expensive equipment. Also,

' clock work type of controls are not adaptable to remote controloperations, nor are they amenable to continuously synchronizing thewells in a given oil field.

Thus, although it is known to employ fluid in a timing arrangement, suchknown arrangement involves as a principal control element one thatincludes a snap acting valve structure. Such valve structure is one thatinvolves mechanical shifting of a rotatable element therein, andconsequently the arrangement is subject to constant wear and thusrelatively short life, or subject to frequent repairs. Finally, it isnot apparent that such prior arrange ment could be adapted for use inremote control arrangements such as is the case with the subjectinvention.

Consequently it is an object of this invention to provide apneumatically powered, timing system that is relatively simple andrugged in its construction.

Another object of the invention is to provide a fluid timer system thatis accurate and positive acting while being simple and inexpensive inconstruction.

Another object of the invention is to provide a pneumatic timingarrangement that is self-actuating, reliable and is readily adaptablefor remote control type of operation which includes arrangements formaintaining exact synchronous relationship between a plurality of timersin a given oil field.

Briefly, the invention concerns a pneumtic timer system which comprisesmeans for receiving compressed gas. The system also comprises a firstcontainer, a second container and a fluid path connecting said first andsecond containers and including two branches. In the foregoing system,each branch includes therein a restriction and a check valve in series.The system also comprises a quantity of liquid in said containers, saidliquid quantity having a maximum volume that is equal to the smaller ofsaid containers in order to permit flow of some gas through said fluidpath following flow of said liquid therethrough. In addition the systemcomprises a fluid pressure operated three-way valve having an operator,and pneumatic circuit means connecting one of said containers to theoperator of said three-way valve and the other of said containers tosaid three-way valve for alternative connection to said receiving meansor to exhaust, whereby introduction of a compressed gas into the systemcauses said liquid to flow from said first container into said secondcontainer and return in a cyclic manner.

Again briefly, the invention relates to a system in combination with agas lift type pump including a source of gas under pressure, and apressure operated control valve. In the foregoing system the inventionconcerns the improvement that comprises a pneumatic timer forcontrolling actuation of said pressure operated control valve whereinsaid timer comprises means for connecting the source of gas underpressure to said timer system. The improvement also comprises a firstcontainer for receiving said gas under pressure, a second container, anda fluid path interconnecting said first and said second containers andhaving two branches. The foregoing branches each contain a restrictionand a check valve in series therewith. The improved system alsocomprises a quantity of liquid freely held in said containers in directcontact with said gas. The said liquid quantity has a maximum volumethat is equal to the capacity of the smaller of said containers. Theimproved system additionally comprisesa fluid pressure operatedthree-way valve having an operator for actuation thereof, and pneumaticcircuit means for connecting said source of gas under pressure to saidthree-way valve and from said three-way valve to said first container.In addition the improved system comprises additional pneumatic circuitmeans for connecting said second container to the operator of saidthree-Way valve and to said control valve, all whereby a continuouscyclic operation takes place causing said control valve to beintermittently opened and closed to introduce into said wellpredetermined pumping quantities of gas under pressure.

The foregoing and other objects and benefits of the invention will bemore fully appreciated in connection with the detailed description whichfollows, and which is illustrated in the drawing, in which:

The figure of drawing shows a schematic system diagram, illustrating atimer according to the invention as connected to a gas lift well.

Referring to the figure of the drawings there is illustrated a gas liftwell 11 that is closed at the top as indicated, and carries thereintubing 12 that extends downhole to the producing formation and includesgas lift valves (not shown) spaced at intervals along its length and apacker (not shown) near the bottom to seal the annulus from the tubing.The tubing 12 acts to accumulate production fluid that is thendischarged upward through tubing 12 when application of gas underpressure is introduced into the tubing from the annulus of the well 11surrounding the tubing. The gas under pressure for causing such gas liftpumping operation is introduced via a pipe 13 that is connected to thewell 11 and that carries in series therewith a main control valve 14,shown schematically in the drawing. The gas under pressure that isdelivered through valve 14 and pipe 13 is drawn from a source ofrelatively high pressure, e.g. a compressor (not shown), and isintroduced through another pipe 17 that is connected to the other end ofthe valve 14. This gas under pressure may be termed power gas asindicated by the caption on the drawing. Ordinarily such gas will be alarge volume source of pressured gas, under relatively high pressure,e.g. 600 pounds per square inch.

The timer system per se is illustrated schematically at the left handportion of the figure of drawings and is shown enclosed in a dashed linebox 18. The elements included in this system are connected with a sourceof pneumatic pressure which in the illustrated arrangement includes apneumatic line 21 that joins the power gas pipe 17 and leads to apressure regulator 22. Pressure regulator 22 reduces the pressure in thepneumatic line at the output side thereof. The output side is connectedvia a pneumatic line 23 that leads to one port of a threeway valve 24.Three-way valve 24 is a fluid pressure operated type, and asschematically illustrated has a diaphragm actuator 29 that ismechanically connected to the valve elements (not shown) that controlpneumatic flow paths including two other ports. One of these ports leadsto exhaust over a pneumatic line 30 while the other is connected to apneumatic line 31 that leads to the upper interior volume of a container32. There is another container 33 that may have greater volume interiorspace than container 32, and that has connected to the upper portion ofthe interior thereof a short pneumatic line 34 which branches into twoseparate pneumatic lines 35 and 36. Pneumatic line 35 leads to apneumatic pressure actuator element 39 of the valve 14, while line 36leads through a restriction 40 to a volume tank 41. Also connected tovolume tank 41 there is another pneumatic line 44 which leads to thediaphragm actuator 29 of three-way valve 24.

From the bottoms of containers 32 and 33 there are fluid line circuitconnections which include two paths 47 and 48, that join together andprovide a common path 49 that is in turn connected into the bottom ofthe container 33. In each of the paths 47 and 48 (in series therewith)there is a restriction 51 and 52 respectively. The restrictions areschematically illustrated, but may take the form of needle valves inorder to provide for adjustment thereof. In addition to therestrictions, there is a check valve 54 and 54 respectively in each ofthe flow paths 47 and 48. These check valves are oriented to permit flowonly in opposite directions through the two paths.

There is a quantity of liquid 60 that may be hydraulic fluid, e.g. oil(as per the caption). This liquid 60 is situated in one or the other orboth of the containers 32 and 33. The amount of liquid 60 ispredetermined such that the total maximum volume thereof is not greaterthan the internal volume of the smaller of the containers 32 or 33. Thereason for this quantity limitation will become clear below, inconnection with a description of the operation.

Operation The operation of the pneumatic timer may be described byfollowing the action of the liquid 60 in the system, as it is shiftedback and forth between containers 32 and 33. It is to be observed thatthis liquid is freely situated within the contaners, so that thepneumatic pressure which is applied to the containers brings thecompressed gas directly into contact with the surface of the liquid.Also, the main control valve 14 is normally closed, i.e. it is biased toa closed position.

A cycle of timing operation may be followed by observing the actioncreated as the power gas in pipe 17 applies pneumatic pressure overpneumatic line 21 and through pneumatic regulator 22 to pneumatic line23 that is connected to an input port of the three-way valve 24. Valve24 is constructed such that it takes up as its normal state (e.g. bymeans of a spring bias) the condition such that the input port (to whichline 23 is connected) is open through to the output port that isconnected to pneumatic line 31, which leads to container 32.Consequently, so long as the three-way valve 24 is in its normal state,the

pneumatic fluid under pressure will enter the upper portion of container32 and apply pressure to the liquid 60 within container 32 thus causingthe liquid to flow over path 47 (via restriction 51 and check valve 53)to the fluid line 49 that leads into the bottom of container 33.Therefore liquid 60 will flow from container 32 into container 33 at arate determined by the opening of the restriction 51. During this liquidflow the gas within container 33 will be gradually compressed somewhat,which compression will be transferred via pneumatic lines 34 and 35 tothe pneumatic actuator 39 of the main valve 14. However, this pressurechange will be slow and will be insufficient to cause enough pressurechange for actuation of main valve 14 during such liquid flow.

When liquid 60 has all flown out of container 32 and past restriction51, the flow of pneumatic fluid through restriction 51 will be rapidcompared to the flow of the liquid and consequently the rate of flow ofthe liquid will suddenly be greatly increased. This rapid increase inflow of liquid 60 will compress the gas in container 33 and in thepneumatic lines connected thereto, so that a suflicient increase inpressure will be applied to the actuator element 39 of valve 14 so as toopen the valve. This, of course, will allow power gas to enter the well11.

Shortly after the actuation of valve 14 by its pneumatic actuator 39,the same rapid increase of pneumatic pressure (existing above the liquid60) in the chamber 33 will cause a delayed pressure increase viarestriction 40 and pneumatic line 36 as well as the volume tank 41 andpneumatic line 44, to act on the diaphragm actuator 29 of three-wayvalve 24. This increase in pressure will then cause three-way valve 24to be actuated from the normal state described above to its other state,such that the input port to which line 23 is connected will be closedWhile the output port that is connected to line 31 will be connected toexhaust via pneumatic line 30. When this delayed action takes place, thethree-way valve 24 will cut off the pneumatic pressure source to thesystem and simultaneously will connect the upper portion of (gas within)container 32 directly to exhaust. Consequently as the gas is exhaustedout of container 32, the liquid 60 will be forced back by reason of thegas under pressure contained above the liquid in container 33.

The return liquid flow will take place via fluid path 49 and path 48 inthis instance, by reason of the orientation of check valve 53 which isclosed to this direction of fluid flow while check valve 54 is open topermit such flow. In this instance the rate of flow of the liquid as itreturns from container 33 back into container 32, will be controlled bythe size of the opening created in restriction 52. Once again (in thisreturn fiow portion of the total cycle) the liquid flow will berelatively slow so that gas pressure above the liquid in container 33and pneumatic lines connected thereto, will remain relatively constanthaving only a slow reduction. Thus, suflicient pressure will remain tomaintain valve 14 open and three-way valve 24 actuated (under pressure)to the last position just described above.

Finally, when the last of liquid 60 flows out of container 33 and pastrestriction 52, the gas flow past restriction 52 will be at an increasedrate by reason of the lower viscosity of the gas, and consequently thepressure in container 33 and connecting lines will be rapidly reduced.Such rapid reduction of pressure will cause the valve 14 to closepositively, as the pressure in its actuator 39 drops, while shortlythereafter three-way valve 24 will return (also with positive action) toits normal state by reason of the pressure reduction within actuator 29thereof. Thus the system is once more returned to its original state andanother complete cycle such as that just described, will commence oncemore.

It will be observed that the continuously repeating cyclesof operation(causing opening and closing of the main valve 14) will automaticallytake place at any predetermined time duration intervals. Such intervalswill be determined by the various factors such as the volume of liquid,the size of openings in restrictions 51, 52 and the viscosity of theliquid dtl, etc. Furthermore it will be noted that the open and closedtime periods for valve 14, may be separately adjusted by individualregulation of the restrictions 51 and 52.

It is pointed out that the various elements such as restrictions 51, 52and 46 as well as three-way valve 24 and check valves 53, 54 etc., areall shown schematically, since any feasible elements may be employedfrom among those commercially available in the field of pneumatic andliquid flow equipment.

As will be observed in connection with a copending application, apneumatic timing system according to this invention is readily adaptablefor interconnection with like units so as to provide for synchronousoperations that cannot get out of step. Furthermore, the timers of thisinvention are adaptable for remote control arrangements, e.g. such asthe one illustrated in the aforementioned copending application.

While a preferred embodiment of the invention has been shown anddescribed in considerable detail in accordance with the applicablestatutes, this is not to be taken as in any way limiting the inventionbut merely as being descriptive thereof.

I claim:

1. A pneumatic timer system comprising means for receiving compressedgas to energize said system, a first container, a second container, afluid path connecting said first and second containers and including twobranches, each branch including therein a restriction and a check valvein series, said check valves being oriented to permit flow in oppositedirections, a quantity of liquid in said containers, said liquidquantity having a maximum volume equal to the smaller of said containersin order to permit flow of some gas through said fluid path followingflow of said liquid therethrough, a fluid pressure operated three-wayvalve having an operator and three ports, one of said ports beingconnected to exhaust, another of said ports being connected to saidreceiving means, and pneumatic circuit means connecting one of saidcontainers to the operator of said three-way valve and the other of saidcontainers to said third port of said three-way valve for alternativeconnection thereof to said receiving means or to exhaust wherebyintroduction of a compressed gas into the system through said receivingmeans causes said liquid to flow from said first container into saidsecond container and return in a cyclic manner.

2. A pneumatic timer according to claim 1 wherein 6 said one containeris connected to a pressure operated output element for actuation thereofupon increase of pressure.

3. A pneumatic timer according to claim 2 wherein said restrictions areadjustable for providing dififerent time duration of the portions of acomplete cycle.

4. A pneumatic timer according to claim 3 further including a volumetank and an additional restriction in series in said circuit meansbetween said one container and the operator of said three-way valve, toensure positive action of said output element.

5. A pneumatic timer for controlling actuation of a pressure operatedcontrol valve comprising input means for connecting a source of gasunder pressure to said timer, a first container for receivingcontrollably said gas under pressure, a second container, a tiuid pathinterconnecting said first and second containers and having twobranches, said branches each containing a restriction and a check valvein series therewith, said check valves being oriented to permit flow inopposite directions, a quantity of liquid freely held in said containersin direct contact with said gas, said liquid quantity having a maximumvolume equal to the capacity of the smaller of said containers, a fluidpressure operated three-way valve having an operator for actuationthereof and having three ports, one of said ports being connected toexhaust, another of said ports being connected to said input means, andpneumatic circuit means for connecting said third port to said firstcontainer, and additional pneumatic circuit means for connecting saidsecond container to the operator of said three-way valve and to saidcontrol valve, said three-way valve being constructed and arranged foralternately connecting said first container to said input means and tosaid exhaust means, all whereby a continuous cyclic operation takesplace upon application of said gas under pressure causing said controlvalve to be intermittently opened and closed.

6. The improvement according to claim 5 wherein said restrictions areadjustable to regulate the time of the corresponding portion of thecycle.

7. The improvement according to claim 6 wherein said additionalpneumatic circuit means includes a volume tank and a restriction in theconnection from said second container to the operator for delayingactuation of said three-way valve relative to said control valve.

Kain Jan. 1, 1952 Canalizo Apr. 10, 1962

1. A PNEUMATIC TIMER SYSTEM COMPRISING MEANS FOR RECEIVING COMPRESSEDGAS TO ENERGIZE SAID SYSTEM, A FIRST CONTAINER, A SECOND CONTAINER, AFLUID PATH CONNECTING SAID FIRST AND SECOND CONTAINERS AND INCLUDING TWOBRANCHES, EACH BRANCH INCLUDING THEREIN A RESTRICTION AND A CHECK VALVEIN SERIES, SAID CHECK VALVE BEING ORIENTED TO PERMIT FLOW IN OPPOSITEDIRECTIONS, A QUANTITY OF LIQUID IN SAID CONTAINERS, SAID LIQUIDQUANTITY HAVING A MAXIMUM VOLUME EQUAL TO THE SMALLER OF SAID CONTAINERSIN ORDER TO PERMIT FLOW OF SOME GAS THROUGH SAID FLUID PATH FOLLOWINGFLOW OF SAID LIQUID THERETHROUGH, A FLUID PRESSURE OPERATED THREE-WAYVALVE HAVING AN OPERATOR AND THREE PORTS, ONE OF SAID PORTS BEINGCONNECTED TO EXHAUST, AN-